Chap. 17.] The Peril oneuM and Mefentery. 207 



its external is rough, and united to the neighbouring 

 mufcles and veflels by the intervention of cellular fub- 

 flance. The cellular texture attached to the perito- 

 neum, and in fome parts included within its duplira- 

 tures, is generally replete with fat. The peritoneum 

 is a denfe but thin and tranfparerit membrane, the ufes 

 of which are to retain the vifcera of the abdomen in 

 their places, and by the fmooth and moift covering* 

 which it affords them, to prevent adhefions of one vif- 

 cus to another ; for which it is excellently adapted by 

 being continually moiftened by a ferous fluid, which 

 proceeds from very minute pores. The exiftence of 

 thefe is proved by fpreading a portion of the perito- 

 neum on the end of the ringer, and then pulling it very 

 tight on all fides ; by thefe means the pores are dilated, 

 and fmall drops may be obferved to proceed from 

 them. 



The mefentery is a production of the peritoneum, 

 and is formed by two laminse of this membrane, in- 

 cluding cellular fubftance. It rifes by a narrow origin 

 from the firft, fecond, and third vertebras of the loins ; 

 it advances forwards, and gradually becomes broader 

 in its progrefs. The mefentery at length embraces the 

 inteftines with its laminae, and thus affords them the 

 coat which they derive from the peritoneum. That 

 part of the mefentery which involves the fmall ihteftines 

 is more properly called the mefentery j that which in- 

 volves the large is diftinguifhed by the term mefoco- 

 lon. The mefentery includes between its laminae all 

 the blood -veflels and nerves which belong to the in- 

 teftines, and allb the numerous lacteal veflels which 

 take up the chyle from the inteftines, and the glands 

 with which thefe veflels are connected. 



The omentum or caul is alfo formed, by a dublica- 



ture of the peritoneum, including thin cellular fubftanc..', 



9 vm& 



